Combined bead loading and apex application system

ABSTRACT

A bead apex subassembly ( 2 ) which is formed simultaneously to the formation of a tire carcass ( 10 ) but independent of and spaced near the tire building machine ( 100 ) is disclosed. The subassembly ( 2 ) is transferred to the tire building drum ( 5 ) preassembled.

TECHNICAL FIELD

This invention relates to a tire component, more particularly, novelbead-apex subassembly and a method of employing the bead-apexsubassembly into a tire carcass.

BACKGROUND OF THE INVENTION

The manufacture of tires involves numerous components and requiresapplying these tire components in a somewhat ordered sequence to form anassembly of components known as a “tire carcass” to which a belt packageand a rubber tread is applied to make a green tire which is thenvulcanized to finish the produce we commonly refer to as a “tire”.

The assembly of tire components, specifically a tubeless type tire,include a liner which forms an air impervious barrier to contain the airunder pressure in the air chamber of a pneumatic tire, one or more pliesreinforced by cords, a chaffer compound applied in two strips, twoannular bead cores and a pair of apexes which are also generally appliedin strips. The bead cores generally are applied over the chaffers. Othercomponents such as sidewall strips, run-flat inserts, shoulder gumstrips, and fabric toe guards can also be applied to form the tirecarcass.

This stage of the tire building process is commonly referred to as the“first stage” of the tire building process. The components are appliedover a cylindrical building drum that usually includes turn-up bladdersand a center bladder to convert the subassembly of tire components froma cylindrical shape to a toroidal shape.

All or almost all the rubber components are usually applied to thebuilding drum in strips. Each strip is wound onto the drum generallyrequiring a 360° revolution, the ends of the strip are then splicedtogether.

To make the assembly process more efficient, it is desirable topreassemble many of these tire component strips. In U.S. Pat. No.5,762,740 a method of laminating several of the components into asubassembly of carcass components is taught. This greatly improves theefficiency of the first stage building process.

The bead and apex have also been combined in a subassembly as is taughtin U.S. Pat. No. 4,933,034. The apex is applied in a strip outwardlyextending from the radially outer or peripheral surface of the annularbead core and then stitched at the ends of the strip. These components,once reassembled, must be stored in such a way that the apex is notdamaged when it is subsequently brought to the first stage tire buildingmachine.

Such prior art subassemblies of an apex strip to a bead core have theapex radially extending in a manner that requires the carcass to beinflated in the central region to bring the apex into contact with thecarcass. After the carcass is inflated, a turn-up of the ply ends andthe sidewall rubber is made in a step commonly referred to as the“inflated turn-up”. This sequencing of forming the carcass requires amore complex method of manufacturing the carcass because the componentsand subassemblies are not applied to the tire building drum in a flatstate.

An object of the present invention is to avoid or eliminate the storageproblems found in making a bead-apex subassembly.

Another object of the invention is to permit the carcass to be builtwith a bead-apex subassembly without requiring an inflated turn-up.

Another object of the invention is to build the bead apex subassemblyat, but not on the first stage building drum, as the carcass is beingconstructed.

DISCLOSURE OF THE INVENTION SUMMARY OF THE INVENTION

The present invention method of making a tire carcass (10) at a firststage tire building machine (100) has the steps of: a) cylindricallyforming one or more strips of tire components (20, 40, 50, 60, 70)around a first stage tire building drum (5), the first stage tirebuilding drum (5) having an axis of rotation; b) forming two annularbead-apex subassemblies (2) at a location in proximity to and spacedfrom the building drum (5), the subassemblies (2) being formed byapplying an elastomeric apex strip (30) to a peripheral or radiallyouter surface (12A) of an annular bead core (12) having an axis ofrotation; c) aligning the axis of rotation of each bead-apex subassembly(2) with the axis of rotation of the tire building drum (5); d)transferring each bead-apex subassembly (2) onto the tire building drum(5); e) applying any additional tire components (20, 40, 50, 60, 70) toform the tire carcass (10) prior to toroidally shaping the carcass (10).Preferably, the step of forming the two bead-apex subassemblies (2)occurs simultaneously with the cylindrically forming the carcass. (10).

In the preferred method, the step of forming two annular bead-apexsubassemblies (2) further includes the steps of placing each bead core(12) on a rotatable support (80) in proximity to but separated from thetire building drum (5) and applying one elastomeric apex strip (30) ontoa radially outer surface (12A) of each bead core (12) as the support(80) is rotated. Most preferably, the step of applying one elastomericstrip (30) to each bead core (12) includes the step of orienting theelastomeric apex strip (30) parallel to the axis of the bead core (12)relative to the width (W) of the strip. The step of applying oneelastomeric. strip (30) to each bead core (12) includes the steps ofstitching the apex (30) to the bead core (12), splicing ends (30A, 30B)of the apex (30) to form the annular bead-apex subassembly (2).

The step of aligning the bead-apex subassembly (2) axis with the tirebuilding drum (5) axis further includes the steps of moving the support(80) to axially align the bead-apex subassembly (2) with tire buildingdrum (5) axis.

The step of transferring the bead-apex subassembly (2) further includesthe steps of removing the annular bead-apex subassembly (2) from thesupport (80) while maintaining axial alignment with the tire buildingdrum (5), moving the support (80) to a location spaced from the tirebuilding drum (5) and moving each bead-apex subassembly (2) onto thetire building drum (5).

The method of forming an annular bead-apex subassembly (2) as anintermediate article of manufacture to be used at a first stage tirebuilding machine (100), the method comprising the steps of: a) placingan annular bead core (12) on to a support (80), the bead core (12)having an axis of rotation; b) applying an elastomeric strip of apex(30) onto a radially outer surface (12A) of the bead core (12), thestrip (30) being applied with the width (W) of the strip (30) beingoriented parallel to the axis of the bead core (12); c) stitching thestrip (30) to the bead core (30); and d) splicing ends (30A, 30B) of thestrips (30), thus, forming the annular bead-apex subassembly (2) as anintermediate article of manufacture to be used at a first stage tirebuilding machine (100).

The resultant methods can yield a bead-apex subassembly (2) as anintermediate article of manufacture having an annular bead core (12)having a radially outer surface (12A); and an elastomeric strip of apex(30) affixed to the radially outer surface (12A) of the bead core (12)at a first end (31) of the strip (30) along a radially inner surface(33), the distances between the first end (31) and a second end (32),defining the width (W) of the strip (30), the width (W) of the strip(30) being substantially oriented parallel to the axis of the bead core(12) along the radially inner surface (33).

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of a first stage tire building machine (100).

FIG. 2 is a side view of the building drum mechanism (5) and bead-apexsubassembly forming station (200).

FIG. 3 is an end view of the bead apex subassembly forming mechanism(200) with a pair of apex stichers shown.

FIG. 4 is an end view of the bead-apex subassembly forming mechanism(200) with a pair of transfer means (202) being shown.

FIG. 5 is a perspective view of the transfer means (202) transferringthe bead apex subassemblies (2) over the building drum (5).

FIG. 6 is an enlarged view of the cross-section of the bead apexsubassembly (2).

FIG. 7 is a perspective view of the formed bead apex subassembly (2).

FIG. 8 is a cross-sectional view of the toroidally-shaped tire carcass(10).

DEFINITIONS

For ease of understanding this disclosure, the following items aredisclosed:

“Apex” means an elastomeric filler located radially above the bead andinterposed between the plies and the ply turn-up.

“Axial” and “axially” means the lines or directions that are parallel tothe axis of rotation of the tire.

“Bead” means that part of the tire comprising an annular tensile membercommonly referred to as a “bead core” wrapped by ply cords and shaped,with or without other reinforcement elements such as flippers, chippers,apexes, toe guards and chafers, to fit the design rim.

“Belt Structure” or “Reinforcing Belts” means at least two annularlayers or plies of parallel cords, woven or unwoven, underlying thetread, unanchored to the bead, and having both left and right cordangles in the range from 17° to 27° with respect to the equatorial planeof the tire.

“Carcass” means an unvulcanized laminate of tire ply material and othertire components cut to length suitable for splicing, or already spliced,into a cylindrical or toroidal shape. Additional components may be addedto the carcass prior to its being vulcanized to create the molded tire.

“Casing” means the tire carcass and associated tire components excludingthe tread.

“Chafers” refers to narrow strips of material placed around the outsideof the bead to protect cord plies from the rim, distribute flexing abovethe rim, and to seal the tire.

“Circumferential” means lines or directions extending along theperimeter of the surface of the annular tread perpendicular to the axialdirection.

“Cord” means one of the reinforcement strands of which the plies in thetire are comprised.

“Equatorial Plane (EP)” means the plane perpendicular to the tire's axisof rotation and passing through the center of its tread.

“Innerliner” means the layer or layers of elastomer or other materialthat form the inside surface of a tubeless tire and that contain theinflating fluid within the tire.

“Insert” means an elastomeric member used as a stiffening member usuallylocated in the sidewall region of the tire.

“Ply” means a continuous layer of rubber-coated parallel cords.

“Radial” and “radially” mean directions radially toward or away from theaxis of rotation of the tire.

“Radial Ply Tire” means a belted or circumferentially-restrictedpneumatic tire in which at least one layer of ply has the ply cordsextend from bead to bead at cord angles between 65° and 90° with respectto the equatorial plane of the tire.

“Shoulder” means the upper portion of sidewall just below the treadedge.

“Sidewall” means that portion of a tire between the tread and the bead.

“Tread” means a rubber component which when bonded to a tire carcassincludes that portion of the tire that come into contact with the roadwhen the tire is normally inflated and under normal load.

“Tread Width” means the arc length of the tread surface in the axialdirection, that is, in a plane parallel to the axis of rotation of thetire.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIG. 1, a side view of an exemplary tire buildingmachine (100) is illustrated. The machine (100) has a tire building drum(5). The building drum (5) has an axis of rotation permitting the drumto rotate. Preferably, the drum is cantilevered or attached to a frameat one end leaving the opposite end free to have annular components suchas a bead core pass over the drum(5). The drum (5) has inflatablebladders (5A) which are used to toroidally shape the central portion ofa carcass and to inflate and, thereby, make the turn-up ends of the plywrap about the bead cores.

At one or both ends of the machine (100) are various mechanisms (102)for supplying strips of elastomeric components used to make a tirecarcass. These mechanisms are often called “let-off devices” which feedstrips of tire material to the building drum (5).

In close proximity to the building drum (5) is a mechanism called an“automatic bead loader”. The bead loader (6) has a pair of annularmembers that can be formed by two semi-circular half rings (6A, 6B). Thepair of bead loaders (6) are pivotally moveable away from and into axialalignment with the tire building drum. The bead loaders (6) are modifiedto be an integral part of the subassembly transfer mechanism (201).

The pair of bead loaders (6) have been modified to move axially relativeto each other. This feature enables the bead loaders to move axiallyinwardly over a pair of bead-apex subassembly forming annular supports(80) each support (80) is rotatable about its own axis of rotation andpivotably moveable into and out of axial alignment with the axis of thebuilding drum (5).

The tire building machine (100) of FIG. 1 can be fully automated or mayrequire an operator (1) to manually cut and splice the components asthey are applied to the tire building drum (5).

To better appreciate the tire building process, the sequence of buildingan exemplary tire is explained below. The components listed below can bevaried for a particular tire construction. Some tires have morecomponents than others. For example, some tires of the tube type may notrequire a liner (50). It is, therefore, understood that the exemplarytire construction is simply to be representative of a typical tirecarcass.

A tire liner (50) is first applied to the tire building drum (5). Then,two shoulder gum strips (40) may be placed onto the liner at spacedlocations axially inward of the edges of the liner (50). The shouldergum strips (40) acts as a rubber reinforcement in the shoulder of thetire carcass.

A hard rubber chafer component (60) is then applied at each of the edgesof liner (50). The chafer (60) are positioned axially to provide a toughrubber reinforcement between the tire and the rim flange of the wheeland is accordingly located in the bead region of the finished tire.

A sidewall component (70) can be attached to and slightly overlappingeach of the chafers (60).

Optionally, to build an outlined white letter tire or a whitewall tire,a whitewall strip (72) and a cover strip (74) may be added to thesidewall areas (70) of the assembly (10). Additionally, runflat inserts(76) may be added in the sidewall region of the assembly. This isparticularly useful in run-flat tire construction.

The above description includes most of the unreinforeed elastomericcomponents required to build a tubeless tire.

Overlying these components may be one or more plies (20).

Each of the components described above requires, if applied separately,a rotation of the building drum (5) to form the component into acylindrical shape. Alternatively, these components may be fed to thetire building machine (100 as one or more subassemblies. In either case,the ends of the components or subassemblies must be spliced together.

The prior art method of tire assembly would next require that the beadcores (12) be slid over an end of the building drum (5) and positionedaxially at a predetermined axial location generally above the chafers(60). Then, an apex filler strip (30) would be placed with an end ontobead core (12) and extending axially inwardly relative to the bead cores(12). The apex filler strips (30) would then be cut to length and thecut ends (30A, 30B) spliced together and then stitched onto theunderlying bead core (20) and tire assembly. The application of the apexfiller strip (30) required additional rotation of the building drum (5)and because the tire cacass is assembled in layers, each layer of stripsmust be accomplished sequentially.

The use of preassembled bead-apex subassemblies (2) can eliminate thetime needed to rotate the drum (5). However, the need to store andmaintain such subassemblies is an added cost in itself.

The present invention teaches the forming of the bead-apex subassembly(2) at or in proximity to the tire building machine (100) yet not on thebuilding drum (5). This enables the subassemblies (2) to be formedwithout affecting or being limited to the building sequence of the restof the carcass (10).

This means that the elastomeric apex strips (30) can be applied to thebead core (12) as shown in FIGS. 1-6.

In the preferred apparatus (200), the apex strip (30) is applied onto aradially outer surface (12A) of a bead core (12) and the rotatablesupport (80) to which the bead core (12) is attached. In the preferredembodiment, the apex strip (30) is applied horizontally relative to thewidth (W) of the strip (30). Once applied, the longitudinal ends (30A,30B) of the strip (30) are cut to length and spliced, preferably thestrips (30) can be precut to length prior to being applied to the beadcore (12) and support (80). Then as shown in FIG. 3, a pair of stitcherwheels (204) presses firmly against the end (31) of the uncured apexstrip (30) attaching it to the bead core (12). As illustrated, each apexstrip (30) extends axially inwardly from each bead core (12) as shown inFIG. 3.

The bead-apex subassembly (2) is then pivoted into axially alignmentwith the axis of the tire building drum (5). Similarly, the bead loaders(6) are positioned into axial alignment with the tire building drum (5).Once aligned, the bead loaders (6) move axially inwardly over the beadcore (12). In the preferred apparatus, the support (80) has a pluralityof small holes (81) underlying the apex strip (30). These holes (81) areconnected to an air vacuum and pressure line. A vacuum is used to holdthe strip (30) in position at least until it is stitched to the beadcore (12). Once the bead loaders (6) are in position to transfer thesubassembly (2) from the support (80), air pressure can be supplied tothe holes (81) helping to release the apex strip (30) from the support(80). At this point, the bead loaders (6), which preferably include amagnetic ring (7), pick up the bead apex subassembly (2) automatically.Alternatively, the bead loaders (6) may use a vacuum or other means tograsp the bead-apex subassembly (2). Once sped, the bead loaders (6)each holding a bead-apex subassembly (2) can move axially apart, thenthe unloaded rotatable support (80) are pivoted out of axial alignmentof the building drum (5). This frees the bead loaders (6) to move overan end (5A) of the building drum (5) to position the beadapexsubassemblies (2) precisely onto the cylindrically-shaped carcass (10)at the location needed to position the bead apex subassembly (2). Thebead loader (6) then releases the bead apex subassembly (2) on the drum(5) while the drum bead locks expands radially under the bead cores (12)locking them into position. Once the bead-apex subassembly (2) istransferred to the building drum (5), the bead loaders (6) are movedback away from the building drum (5).

The tire building sequence then inflates the turn-up bladders andstitched the turn-up ends onto the carcass (10). The central portion ofthe drum (5) can be inflated toroidally as shown in FIG. 8.

One unique feature of the preferred method of forming the bead-apexsubassembly (2) is that the apex (30) lies horizontally on top of thebead core (12). This feature is unusual in terms of the cantilevering ofthe uncured apex strip (12). Storage and preassembly away from the tirebuilding machine (100) would be very difficult. However, because thesubassembly (2) is formed simultaneously with the carcass assembly (10),it can be directly transferred onto the building drum (5) with nodifficulties in handling or storage.

This method of assembly can speed up the time required to form a carcass(10) by about 16%. This is a sizable cost savings that could not befully realized on tire building machines (100) that did not have aninflated turn-up capability.

The above disclosed process can be automatic, if required, with theapplication of the apexes preformed by a device and cut to lengthwithout the need for an operator. Alternatively, the process can besemi-automatic requiring an operator cut the apex to length.

What is claimed is:
 1. A method of making a tire carcass at a firststage tire building machine, the method comprising the steps of: a)cylindrically forming one or more strips of tire components around afirst stage tire building drum, the first stage tire building drumhaving an axis of rotation; while simultaneously forming two annularbead apex subassemblies at a location in proximity to and spaced fromthe building drum, the subassemblies being formed by applying anelastomeric apex strip to a radially outer surface of an annular beadcore having an axis of rotation; the apex strip when applied to the beadcore being oriented parallel to the axis of the bead core relative tothe width (W) of the strip; b) aligning the axis of rotation of eachbead-apex subassembly with the axis of rotation of the tire buildingdrum; c) transferring each bead-apex subassembly onto the tire buildingdrum; d) applying any additional tire components to form the tirecarcass prior to toroidally shaping the carcass.
 2. The method of claim1 wherein the step of forming two annular bead-apex subassembliesfurther includes the steps of placing each bead core on a rotatablesupport in proximity to but separated from the tire building drum andapplying one elastomeric apex strip onto a radially outer surface ofeach bead core as the support is rotated.
 3. The method of claim 2wherein the step of applying one elastomeric apex strip to each beadcore includes the steps of stitching the apex to the bead core, andsplicing ends of the apex to form the annular bead-apex subassembly. 4.The method of claim 3 wherein the step of aligning the bead-apexsubassembly axis with the tire building drum further includes the stepsof moving the support to axially align the bead-apex subassembly withtire building drum axis.
 5. The method of claim 4 wherein the step oftransferring the bead-apex subassembly further includes the steps ofremoving the annular bead-apex subassembly from the support whilemaintaining axial alignment with the tire building drum, moving thesupport to a location spaced from the tire building drum and moving eachbead-apex subassembly onto the tire building drum.